Abstract-Lung lavage effectively removed inhaled radioactive particles from the lungs in a variety of animal experiments. Several types of lung lavage procedures were used. The removal of several different radionuclides has been studied, including 95Zr-95Nb, 144Ce, 239Pu, 238Pu and 241Am. A single lung lavage in a beagle dog removed about 12% of the initial lung burden (ILB) of the inhaled material. Multiple lung lavages have removed up to 50% of the ILB. A single lung lavage in beagle dogs performed between 2 and 196 days after a single inhalation exposure removed the same percentage of the existing lung burden of 144Ce particles. It was also found that inhaled material with a short lung retention time is poorly removed from the lung by lavage. The removal of radioactive particles with long lung retention times was similar for beagle dogs, baboons and one human. Lung lavage and chelating agents were found effective when used together. In one experiment, the use of lung lavage removed substantial amounts of 144Ce in fused aluminosilicate particles from beagle dogs and prevented the clinical appearance of radiation pneumonitis to 18 months after exposure, whereas, other dogs exposed to the same amounts of 144Ce, but not given lung lavages, died in less than 9 months.